Occupant restraint systems that include deployable occupant protection devices, such as air bags, for motor vehicles are well known in the art. Typically, these systems include one or more sensors that detect crash stimulus, for example, vehicle deceleration which is commonly referred to as crash acceleration, and an airbag that deploys when a controller energizes an igniter of the airbag. For example, when the igniter is energized, it releases or initiates a flow of inflation fluid from a reservoir or other storage device into the air bag, inflating it.
In some known occupant restraint systems, the deployable occupant protection device inflates in multiple stages. This allows the device to partially inflate or deploy in crash instances that are relatively less severe or fully inflate or deploy in crash instances that are relatively more severe. Typically, multiple inflation fluid reservoirs or other storage devices and multiple sensors are used in such systems.
The controller in such systems is configured to differentiate between low level deployment events, mid level deployment events, and high level deployment events, using any of a variety of known algorithms. These known algorithms typically use integration functions for signal processing and evaluating the resultant values versus predetermined criteria in determining crash occurrence or severity. Examples of such known algorithms are illustrated in, for example, U.S. Pat. No. 5,587,906; U.S. Pat. No. 5,935,182; U.S. Pat. No. 6,036,225; and U.S. Pat. No. 6,186,539.
U.S. Pat. No. 5,587,906 discloses an air bag restraint system where a crash acceleration value is integrated to provide a crash velocity value and to partially determine a crash metric value. The crash metric value is compared to threshold values to determine whether to deploy the air bag.
U.S. Pat. No. 5,935,182 discloses an air bag restraint system where a crash acceleration value is determined as a function of crash velocity and crash displacement using integrating functions. The crash acceleration value is then processed using an occupant spring-mass model for adjusting the crash acceleration signal. Air bag deployment decisions are made based on the adjusted crash acceleration signal.
U.S. Pat. No. 6,036,225 discloses an air bag restraint system that can be deployed in multiple stages. A signal indicative of acceleration is integrated to provide a velocity signal which is processed to determine a velocity value. When the velocity value exceeds a first threshold value, a first deployment stage is initiated. When the velocity value exceeds a second threshold value, a second deployment stage or complete deployment is initiated.
U.S. Pat. No. 6,186,539 discloses an air bag restraint system that can also be deployed in multiple stages. An average crash acceleration value is determined by processing signals from multiple crash sensors, and is compared against a crash severity index. When the average crash acceleration value exceeds a first threshold value, a first deployment stage is initiated. When the average crash acceleration value exceeds a second threshold value, a second deployment stage or complete deployment is initiated.
Such efforts have proven beneficial and successfully increase occupant safety during crash events. Although these systems are successful and sufficient, further technological developments could prove desirable. For example, during offset deformable barrier (ODB) crash tests, and analogous actual impact or crash events, considerable signal fluctuation occurs due to energy absorption and yielding and corresponding positive and negative acceleration signals during early stages of impact, whereby innovative signal processing might prove desirable.
Accordingly, it could prove desirable to provide a vehicle that incorporates a deployable occupant protection device that is controlled by processing which can accurately account for high magnitude and high frequency signal content, varying between positive and negative values.
It could also prove desirable to provide a vehicle that incorporates a deployable occupant protection device that uses a supplemental algorithm to enhance performance of a known crash algorithm.
It could also prove desirable to provide a supplemental algorithm that preliminarily processes crash signals transmitted by crush zone crash sensors, so that resultant values are easily accommodated by a known crash algorithm.
It could also prove desirable to provide a supplemental algorithm that improves accuracy of deployment decisions during angular, oblique, or offset front end collision events.
It could also prove desirable to provide a supplemental algorithm that leads to quicker deployment initiation decisions during angular, oblique, or offset front end collision events.